With regard to the identifying properties by which, in the writer's opinion, the actual trajectories of ocean currents can be more confidently traced than by the dynamic topographic method (see preceding acticle, Parr 1938, a) nothing much needs to be said in the present article. To the extent that these properties do serve to identify water masses of the same derivation in the course of their movement and their gradual changes, and do differentiate these water masses from those of other origins, the validity of the conclusions to be drawn from a study of the distribution of these properties would seem beyond dispute....